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Parkinson's, autoimmunity, and oat milk
June 2025 | Gut Advisor Monthly Newsletter
Lisa Goehler
June 21, 2025
Hi friends,
Welcome to our second edition of the Gut Advisor Newsletter! This is a monthly newsletter where we address new (or older, but relevant) research findings as well as summarize recent findings or gut-related news. Here, “gut-related” is broadly interpreted, so we will be covering anything that might affect the gut, both “top down” and “bottom up”. This means brain/mind things (“top down”) such as psychology of stress, resilience, and emotion regulation, as well as body-based things (“bottom up”) including inflammation and typical comorbidities of gut disorders, such as pain conditions and autoimmunity.
Dr. Lisa Goehler
Table of Contents
Links between the gut and non-gut disorders like Parkinson’s Disease and Lupus
These two papers link guts factors (gut microbes and diet) to two (what I like to call) non-gut gut disorders: autoimmunity and Parkinson’s Disease.
Ultraprocessed foods and Parkinson’s Disease
A paper appearing in the journal Nature1 reported a very painstaking study of markers and mechanisms associated with the autoimmune disease lupus. Lupus is challenging to manage and can be deadly, as there is no cure. The study linked a cellular pathway that can be influenced by our old friend butyrate as a potential therapeutic target for treating lupus.
The journal Neurology just published a paper linking consumption of ultraprocessed foods with early symptoms of Parkinson’s Disease3. The study showed that high consumption of foods such as soda, processed meats and snack foods was associated with a two and a half times risk of having symptoms including constipation, smell deficits, REM sleep disorder, and depression. This constellation of symptoms is indicative of a very high risk of developing Parkinson’s Disease.
These findings reinforce previous findings linking diet to risk for Parkinson’s Disease (PD). In 2020, Molsberry et al. reported that adherence to a Mediterranean type diet was associated fewer prodromal signs of PD, such as constipation, REM sleep disorder and daytime sleepiness, and depression4 .
Take home message
Overall, the finding support other studies that have indicated that Parkinson’s Disease can begin in the gut5,6 . There has been a longstanding association of toxin exposure to idiopathic (non-genetic) case of Parkinson’s7 , and it may be that the industrialization of food production may generate food constituents that drive the development of Parkinson’s Disease. This is a very good reason to cut back on ultra-processed foods!
Lupus: Potential therapeutic pathway of fiber
The pathway that the researchers identified can be influenced by something called the aryl hydrocarbon receptor, which among other things can have anti-inflammatory and immune regulatory actions. A key influence on the aryl hydrocarbon receptor are the short chain fatty acids, including butyrate.
Butyrate is the source of energy for the gut lining cells that absorb our food. Nearly all of the butyrate that the gut lining needs is provided by certain microbes that depend on our diet for their survival. We are not able to make butyrate ourselves, so we rely on microbes. Butyrate can downregulate inflammation in the gut2 and the findings from this report indicate that butyrate could also be a therapeutic target for lupus.
Take home message
The paper describes another way in which the gut can influence systemic immune function. Because the principal source of butyrate comes from microbes and microbes depend on diet, the findings underline the importance of diet for autoimmunity beyond gut. In case you don’t know, the main food for butyrate-producing microbes is fiber, both soluble and insoluble.
An understandable discussion of the paper can be found here
Methylene Blue: a biohack or just a hack
Methylene Blue is a molecule used medically as a treatment for a problem with the protein hemoglobin (methemogobinemia), for cyanide poisoning, and for treatment resistant vasodilatory shock. I know it, though, from its common use as a dye (counterstain) for tissue in anatomy preparations and in some conditions screening for tissue changes that might signal cancer (e.g. during colonoscopy). It really makes things blue!
So I was surprised to find that it is being touted in platforms including Reddit and TikToK as a treatment (or preventative) for neurodegeneration, depression, anxiety. Is this even safe? How likely is this to be actually effective, rather than just a great inducer of placebo effects?
“Off label” use
Due to effects on mitochrondria that may convey “neuroprotection” from oxidative stress or other neurodegenerative factors8,9 , some in the psychiatric pharmaceutical world (which is always looking for new drugs) are pushing this as the next new miracle drug. An advantage is that it is already approved for human clinical use, so it would not have to go through the FDA approval process. It can be used “off label”. For FDA approval, it would need to be shown that the drug is both effective and safe. Safe could be a problem.
Can it be an anti-depressant?
It has been suggested to be anti-depressant because it can block an enzyme called monoamine oxidase (MAO), and other drugs that do this have antidepressant actions. However, it can also cause a condition called “serotonin syndrome”, particularly when a person is also taking, or recently took, other antidepressant drugs10 . Serotonin syndrome is a life-threatening condition that can include diarrhea, fever, neurological dysfunction, and seizures.
Another concern is that clinically approved use of methylene blue is usually used for acute situations, rather than chronically as it would need to be for anti-depressant use or to protect against neurodegeneration. One obvious concern about this would be stress on kidneys from having to clear it, as well turning urine and soft tissues (like mouth) blue. But a study from 2023 looking at whether methylene blue actually improves brain metabolism and blood flow11 found to their surprise - just the opposite. Importantly, they used the roughly same dose that others have used to study memory enhancement.
Is it safe?
One big concern is that methylene blue is being touted as a supplement, and thus could/is ingested without any medical supervision. This is of particular concern because methylene blue is well known for its “hermetic effects”8 . This means that is has different, even opposite effects, depending on the dose. How carefully will people using it as a supplement be about using a safe dose?
It is also a “dirty” drug, in that has several different mechanisms of action on different systems, which means it is a high risk for side effects, potentially very bad side effects. This is probably why the mainstream pharmaceutic companies have not jumped on it.
There IS evidence that under the proper circumstances, methylene blue may have beneficial effects on the brain. But it is risky, and mainstream pharmaceutic companies are highly risk averse (unlike supplement companies, they can get sued).
In this case, I would say that risk averse is good.
Oat milk is pro-inflammatory, has a high glycemic index, has toxins in it, and isn’t as nutritious as real dairy
Where did this claim come from?
I have no idea precisely where the claim that oat milk is pro-inflammatory comes from. Perhaps based on the “toxins” it supposedly has, or perhaps (as I have noticed lately) being pro-inflammatory is just a non-specific accusation of being bad. (Most people don’t really understand inflammation anyway).
In any case a randomized clinical trial of oat-enriched diet for people with type 2 diabetes showed that increased consumption of oats was associated with fewer markers of inflammation12. Overall, studies investigating oats and inflammation have found either mild anti-inflammatory effects, or no effects.
Let’s break this down
Glycemic index
Oat milk does have a higher glycemic index than other diary or diary substitutes, even though it is made of oats, which have a low glycemic index. This is because the oats are ground, and thus making the sugars in it more quickly absorbable. The real concern here is when commercial sources of oat milk add extra sugars to the oat milk13,14.
Lectins
Oat milk does have lectins in it, as all plants have lectins. Lectins are proteins that can have a variety of effects on cells, including negative effects, depending on the type of lectin. The food group with the highest concentration of lections are the seeds of beans. It needs to be said that the beans we eat are not the ones, such as castor beans, that high lectin content. Lectins are destroyed by cooking, so cooked beans are “safe”. In oats, the levels of lectins are too small to have consequences for health15 and are typically cooked first also.
Nutrition facts
It is also true that oat milk lacks the important nutrients that dairy contains, but this is true of all of the dairy substitutes14. Commercial dairy alternatives are typically supplemented with vitamins, minerals and/or protein to bring them more in line with dairy nutrition.
Overall, we’re OK with oatmilk!
So, the grain of truth is that pure oat milk (that does not have added nutrients) is less nutritious than dairy milk. This should not be a serious concern unless the oat milk is the major food source being consumed.
The claims of “lectins”, “toxins”, and “inflammation” are hooey!
This month’s selected article
TitleBidirectional brain-gut axis effects influence mood and prognosis in IBD: a systematic review and meta-analysis. | AuthorsFairbrass KM, Lovatt J, Barberio B, Yuan Y, Gracie DJ, Ford AC. PublicationGut., 2022 |
The two-way connection between the brain and gut affects mood and health outcomes in people with IBD: a review of existing studies.
We think this paper is worth a read! Check it out →
Overview
The paper is a systematic review and meta-analysis addressing gut-brain interactions that may drive relationships between depression, anxiety, and adverse health outcomes (measured as, for example, escalation of therapy, hospitalization, emergency department visits) in patients with inflammatory bowel disease (IBD). The authors reviewed papers that reported either relationships of mood symptoms with worsening IBD, or relationships between IBD symptoms and occurrence or worsening of mood symptoms.
The findings reinforce the concept of gut-brain interaction, in that baseline anxiety and depression symptoms predicted adverse health outcomes, supporting a role of top-down influence on IBD. They also found that clinically active disease at baseline predicted the development of anxiety and/or depression, supporting a bottom-up influence on mood.
Why is this important?
Whereas scientists and practitioners have accepted the idea that interactions between the gut and the brain are bidirectional for Functional Bowel Disorders (now called Disorders of Gut Brain Interaction) for nearly twenty years, this idea has been slower to permeate the world of IBD. The use of the meta-analysis, including multiple studies, allows the authors to provide a more convincing story than the results of just one study would.
So, overall, the study re-enforces the idea that what is happening in the gut links to brain functions including regulation of mood. Similarly, factors that drive mood symptoms, such as stress, are pathophysiologically important for outcomes in IBD.
Take home message
Treatment approaches for inflammatory bowel diseases need to address both gut and brain. This means that lifestyle factors, such as diet, that can influence IBD symptoms16 may also influence mood. Similarly, medical approaches to IBD, including drugs and surgery, may be enhanced with interventions targeted towards psychological resilience. Thus, the best outcomes are likely to follow form targeting both bottom-up and top-down gut and brain-related factors
Everything Bagel Salmon Sandwich Salad
“Everything bagels” are my favorite, so I was excited when my friend made a salad for a party based on my favorite bagel sandwich, the “Smoked Salmon Everything Bagel”. Basically it is everything you would find in a smoked salmon sandwich.
Ingredients
Dressing
| Steps
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Enjoy!
Our Smoked Salmon Salad Bagel Sandwich Salad
Community Affairs
What do you want to read next month?
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I would like to have a community-led section in this newsletter where readers can share their personal “pro-tips” or experiences surrounding their gut health. If you would like to be featured, you can respond to this email directly with any tips or stories!
 | About the AuthorLisa E. Goehler, Ph.D. is a neuroscientist and expert in the science and treatment of psychological stress, chronic inflammation, and gut-related disorders. She has received numerous grants, authored over fifty publications, and contributed to peer review for scientific journals and funding agencies, including the National Institute for Health. She also pioneered the study of how GI-tract related bacteria can interact with the brain to lower mood and increase anxiety. |
References
1 Law, C., Wacleche, V.S., Cao, Y. et al. Interferon subverts an AHR–JUN axis to promote CXCL13+ T cells in lupus. Nature 631, 857–866 (2024). https://doi.org/10.1038/s41586-024-07627-2
2 Kim S, Seo SU, Kweon MN. Gut microbiota-derived metabolites tune host homeostasis fate. Semin Immunopathol. 2024 Jul 11;46(1-2):2. doi: 10.1007/s00281-024-01012-x. PMID: 38990345; PMCID: PMC11239740.
3 Wang P, Chen X, Na M, Flores-Torres MH, Bjornevik K, Zhang X, Chen X, Khandpur N, Rossato SL, Zhang FF, Ascherio A, Gao X. Long-Term Consumption of Ultraprocessed Foods and Prodromal Features of Parkinson Disease. Neurology. 2025 Jun 10;104(11):e213562
4 Molsberry S, Bjornevik K, Hughes KC, Healy B, Schwarzschild M, Ascherio A. Diet pattern and prodromal features of Parkinson disease. Neurology. 2020 Oct 13;95(15):e2095-e2108.
5 Dogra N, Mani RJ, Katare DP. The Gut-Brain Axis: Two Ways Signaling in Parkinson's Disease. Cell Mol Neurobiol. 2022 Mar;42(2):315-332. doi: 10.1007/s10571-021-01066-7. Epub 2021 Mar 2. PMID: 33649989; PMCID: PMC11441216.
6 Montalbán-Rodríguez A, Abalo R, López-Gómez L. From the Gut to the Brain: The Role of Enteric Glial Cells and Their Involvement in the Pathogenesis of Parkinson's Disease. Int J Mol Sci. 2024 Jan 20;25(2):1294. doi: 10.3390/ijms25021294. PMID: 38279293; PMCID: PMC10816228
7 Tsalenchuk M, Gentleman SM, Marzi SJ. Linking environmental risk factors with epigenetic mechanisms in Parkinson's disease. NPJ Parkinsons Dis. 2023 Aug 25;9(1):123. doi: 10.1038/s41531-023-00568-z. PMID: 37626097; PMCID: PMC10457362
8 Rojas JC, Bruchey AK, Gonzalez-Lima F. Neurometabolic mechanisms for memory enhancement and neuroprotection of methylene blue. Prog Neurobiol. 2012 Jan;96(1):32-45. doi: 10.1016/j.pneurobio.2011.10.007. Epub 2011 Nov 3. PMID: 22067440; PMCID: PMC3265679.
9 Alda M. Methylene Blue in the Treatment of Neuropsychiatric Disorders. CNS Drugs. 2019 Aug;33(8):719-725. doi: 10.1007/s40263-019-00641-3. PMID: 31144270.
10 Schumacher LD, Blumer V, Chaparro SV. Methylene blue-induced serotonin syndrome after left ventricular assist device implantation: A case report and literature review. J Thorac Cardiovasc Surg. 2017 Sep;154(3):e39-e43. doi: 10.1016/j.jtcvs.2017.05.053. Epub 2017 May 24. PMID: 28655448.
11 Singh N, MacNicol E, DiPasquale O, Randall K, Lythgoe D, Mazibuko N, Simmons C, Selvaggi P, Stephenson S, Turkheimer FE, Cash D, Zelaya F, Colasanti A. The effects of acute Methylene Blue administration on cerebral blood flow and metabolism in humans and rats. J Cereb Blood Flow Metab. 2023 Nov;43(2_suppl):95-105. doi: 10.1177/0271678X231157958. Epub 2023 Feb 21. PMID: 36803299; PMCID: PMC10638993.
12 Zhang X, McGeoch SC, Megson IL, MacRury SM, Johnstone AM, Abraham P, Pearson DW, de Roos B, Holtrop G, O'Kennedy N, Lobley GE. Oat-enriched diet reduces inflammatory status assessed by circulating cell-derived microparticle concentrations in type 2 diabetes. Mol Nutr Food Res. 2014 Jun;58(6):1322-32. doi: 10.1002/mnfr.201300820. Epub 2014 Mar 7. PMID: 24604886.
13 Yu Y, Li X, Zhang J, Li X, Wang J, Sun B. Oat milk analogue versus traditional milk: Comprehensive evaluation of scientific evidence for processing techniques and health effects. Food Chem X. 2023 Sep 3;19:100859. doi: 10.1016/j.fochx.2023.100859. PMID: 37780279; PMCID: PMC10534225.
14 Ramsing R, Santo R, Kim BF, Altema-Johnson D, Wooden A, Chang KB, Semba RD, Love DC. Dairy and Plant-Based Milks: Implications for Nutrition and Planetary Health. Curr Environ Health Rep. 2023 Sep;10(3):291-302. doi: 10.1007/s40572-023-00400-z. Epub 2023 Jun 10. PMID: 37300651; PMCID: PMC10504201.
15 Adamcová A, Laursen KH, Ballin NZ. Lectin Activity in Commonly Consumed Plant-Based Foods: Calling for Method Harmonization and Risk Assessment. Foods. 2021 Nov 13;10(11):2796. doi: 10.3390/foods10112796. PMID: 34829077; PMCID: PMC8618113.
16 Hashash JG, Elkins J, Lewis JD, Binion DG. AGA Clinical Practice Update on Diet and Nutritional Therapies in Patients With Inflammatory Bowel Disease: Expert Review. Gastroenterology. 2024 Mar;166(3):521-532. doi: 10.1053/j.gastro.2023.11.303. Epub 2024 Jan 23. PMID: 38276922.